add initial devcontainers

[msarahan]

This is working towards building wheels, but it has benefits for making development more unified with other RAPIDS projects.

At time of writing, this PR is not enough to get wheels working. In particular, there are some annoying issues to resolve:

• dependencies.yaml does not account for CUDA-version-specific version names in package names, like rmm-cu12. That means the package names just don't resolve for wheel builds. This PR attempts to add that using the matrix mechanism.
• rapids-dependency-file-generator doesn't allow the matrix mechanism for pyproject.toml outputs. Paul pointed me to feat: support matrices and stdout for all output types dependency-file-generator#48 as the feature that is needed to resolve this.

As a hacky workaround just to try to get a wheel built, I changed pyproject.toml manually for a cuda 12 build. This is part of the "DO NOT MERGE" commit. This change would affect or break the conda build, so it should not go in. This file needs to be generated during build, not committed with changes.

Even with the pyproject.toml changes, we have a cmake build error:

      CMake Error in ucxx/_lib/CMakeLists.txt:
        Imported target "ucxx::ucxx" includes non-existent path
      
          "/home/coder/ucxx/cpp/build/release/include"
      
        in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:
 
        * The path was deleted, renamed, or moved to another location.
        * An install or uninstall procedure did not complete successfully.
        * The installation package was faulty and references files it does not
        provide.

Paul says "Looks like it's added a path to the build dir in its public interface." I don't know what that means, but I think the next step is debugging in CMakeLists.txt.

[bdice]

Suggested change

	output: [conda, pyproject]
	output: conda

[bdice]

Suggested change

	- librmm==24.02.*
	- librmm==24.2.*

[bdice]

We want to handle this with something like cudf's use of alpha_spec in a script: https://github.com/rapidsai/cudf/blob/6abef4a4746f1f9917711f372726023efdc21e85/ci/build_wheel.sh#L28-L35

[bdice]

Let's diagnose the root cause for this upper bound before merging.